Structural-constraint-driven thermo-fluid topology optimization of load-bearing cooling channels

Load-bearing cooling components must remove heat, sustain loads, and limit pumping loss. This work develops a three-dimensional density-based topology optimization framework coupling incompressible flow, convective heat transfer, and linear elasticity using an adjoint-assisted finite-volume formulation. A filtered and projected design variable interpolates fluid, thermal, and elastic properties, while separately scaled thermal and hydraulic sensitivity channels are combined by w and supplied to MMA under fluid-volume and compliance constraints. Weighting factor, initial configuration, and load magnitude are examined. Optimized layouts evolve from pillar arrays into branched skeletons that guide flow, redistribute heat, and transmit load. Topology optimization is performed at Re = 2200 using a steady laminar model. Reconstructed geometries are evaluated over Re = 1000–10000 using laminar and shear-stress-transport (SST) k - ω models in the lower- and higher-Reynolds-number regimes, respectively. For w = 0.4, these model-consistent paired comparisons show that the average heating-surface temperature, pressure drop, and drag coefficient decrease by 7.0 %-13.3 %, 30.7 %-44.4 %, and 28.5 %-43.0 %, respectively, while the Nusselt number increases by 12.9 %–32.1 %. Separate structural validation shows reductions of 91.0 % and 75.0 % in average and maximum displacements, respectively, with the solid fraction increasing from 2.90 % to 3.45 %. The load-magnitude study further shows that mechanical demand actively reshapes the optimized architecture: increasing the applied load from 1 to 5 MPa transforms relatively open, flow-oriented layouts into denser and more continuously connected load-bearing skeletons. These results show that structural constraints govern the compromise among heat removal, hydraulic loss, and load-bearing capacity.